U.S. Pat. No. 4,632,837 to Erwin Schultz et al. describes a process for the extraction of lutein from plants as Dill, Terragon leaves, Cassia buds and Mimosa flowers using supercritical carbon dioxide at 0° C. to 40° C. and a pressure of 80-200 bar. Separation of the resultant extract was achieved by dissolving it in diethyl ether or pentane at 20-60 bar and 0° C. to 20° C. The process is distinguished by the low pressure extraction and separation using the solvent and is not specific for Tagetes species-marigold flower.
U.S. Pat. No. 6,106,720 to J. S. Kanel et al
The process uses fluid/dense gas extraction of carotenoid from brine containing algae, carrot juice and tomato skin under enhanced solubility conditions comprising flowing a supercritical fluid carbon dioxide pre-saturated with water in a column up to 677 bar and 101° C. The process is distinguishable by extracting the total carotenoids.
U.S. Pat. No. 5,382,714 to F. Khachik
The process for isolation, purification and re-crystallization of lutein from saponified marigold oleoresin comprising the mixing of a saponified marigold extract with an alcohol/water mixture, lowering the temperature to precipitate lutein crystals, washing the crystals with water. The processing is distinguishable by using the saponification and organic solvents.
U.S. Pat. No. 4,048,203 to T. Philip
Purification of lutein fatty acid esters from marigold flower petals or its oleoresin was achieved by using alkanols. This process is distinguished for the use of alkanols.
U.S. Pat. No. 4,466,923 to J. P. Friedrich
The lipid containing materials such as vegetable seed, cereal seed germ and animals meat are extracted for lipids by simultaneous application of temperatures 40-80° C. and pressures up to 1033 bar. The process is distinguishable for the recovery of lipids.
U.S. Pat. No. 4,493,854 to J. P. Friedrich et al.
This process describes the process for defatting of the soybeans products
U.S. Pat. No. 4,511,508 to H. R. Vollbrecht et al.
The process for drying natural extracts of hop pellets, fresh hops and chamomile blossoms by using supercritical fluid extraction technology has been described. The process is distinguished by drying process of the herbal materials.
U.S. Pat. No. 6,689,400 to Majeed Muhammed
The present invention concerns methods of obtaining stable lutein and its derivatives. Additionally, the invention concerns various compositions comprising lutein, lutein esters, tetrahydrocurcuminoids, and carnosic acid. The process of invention is about mainly extraction of marigold flowers using solvent alcohol and stabilization of obtained lutein using with a stabilizing mixture of tetrahydrocurcuminoids and curcuminoids.
PCT/IB01/02057 and U.S. Patent Publication No. 20040267033 to J. R. Rao et al.
A two stage process for the extraction of lutein diester to achieve 10-15% lutein diester in first stage has been described by using 200-350 bar pressure and 40-80° C. temperature. Lutein diester up to 20-25% has been only achieved in the second stage while the purification of lutein. The process is distinguished by low purity lutein diester, 10-15% in first stage and 20-25% in second stage and has been achieved only by using two stage process and the process parameters like pressure 200-350 bar, temperature 40-80° C. for the first stage and 60-140 bar, 15-25° C. were maintained in the second stage.
U.S. Pat. No. 6,909,021 to Lance B. Crombie.
The invention provides a method for extracting carotenoids from green plant materials using supercritical fluid extraction. A first and second supercritical fluid extraction is performed on the green plant composition at two different pressures to obtain two extracts. The first extract includes substantial amounts of .beta.-carotene. The second extract may have a controlled concentration of .beta.-carotene, and includes substantial amounts of lutein. This patent is mainly distinguished by method for extracting mixed carotenoids β-carotene with lutein from green plant alfalfa dry juice curd but not of specific marigold flower meal lutein ester.
U.S. Patent Publication No. 20090247633 to Lance B. Crombie
A method for the separation of carotenoids, especially lycopene, from fruits and vegetables, especially tomatoes. A mixture of powdered fruit and/or vegetable and an edible oil is subjected to supercritical-CO2 fluid extraction. A mixture of the oil and lycopene is separated. Lycopene of food grade quality is obtained. This patent mainly distinguished by method for extracting mixed carotenoids between 30-40 weight % lutein with β-carotene and fatty acids from green plant alfalfa dry protein curd but not of specific marigold flower meal lutein ester. Also finally the obtained carotenoids with fatty acids are formulated with cyclodextrin in ethanol medium.
U.S. Patent Publication No. 20050266132 to Temelli, Feral et al.
A method for separating carotenoids from carotenoid-containing material comprising sizing a carotenoid-containing material, passing a mixture of oil and supercritical CO2 (SC—CO2) continuously through the carotenoid-containing material at conditions effective to extract a carotenoid into the mixture of oil and SC—CO2, and collecting the carotenoid-containing oil. The invention described is mainly about the extraction of carotenoids specifically β-carotene from carrot on lab scale with SCF—CO2 pressures of less than 510 bar in presence of canola oil as co-solvent.
During the past decade, many persons have identified, and quantified carotenoids from fruits and vegetables commonly consumed. These studies have revealed that as many as 40 to 50 carotenoids may be available from the diet and absorbed, metabolized, or utilized by the human body (Khachik et al. 1991, Pure Appl. Chem., 63: 71-80). However, among these, only 13 carotenoids and 12 of their stereoisomers are routinely found in human serum and milk (Khachik et al. 1997, Anal. Chem. 69:1873-1881). In addition, there are 8 carotenoid metabolites and one stereoisomer in human serum or plasma which results from a series of oxidation-reduction reactions of three dietary carotenoids namely lutein, zeaxanthin and lycopene. These metabolites were first isolated and characterized by Khachik et al. (1992, Anal. Chem. 64: 2111-2122). In another study, the ingestion of purified supplements of dietary (3R,3′R,6′R)-lutein and (3R,3′R)-zeaxanthin was shown to, not only, result in an increase in the blood levels of these compounds in humans but also increased the concentration of their oxidative metabolites in plasma (Khachik et al. 1995, J. Cellular Biochem. 22: 236-246).
Bone et al. (1985, Vision Res. 25: 1531-1535; 1993, Invest. Ophthalmol. Vis. Sci. 34: 2033-2040) demonstrated that the human macular pigment is a combination of lutein and zeaxanthin and speculated that these dietary carotenoids may play an important role in the prevention of eye disease namely, Age-Related Macular Degeneration (ARMD). This was later confirmed in a case-controlled epidemiological study in which the high consumption of fruits and vegetables, rich specifically in lutein and zeaxanthin, was correlated to a 43% lower risk of ARMD (Seddon et al. 1994, J. Am. Med. Assoc. 272: 1413-1420). More recently, in addition to lutein and zeaxanthin, the author and his co-workers reported the isolation and identification of one major and several minor oxidation products of lutein and zeaxanthin in human and monkey retinas (Khachik et al. 1997, J. Invest. Ophthalmol. Vis. Sci. 38: 1802-1811)
Although lutein and zeaxanthin is obtained from certain fruits and vegetables, the isolation of lutein from extracts of marigold flowers proves to be most economical. In Marigold flowers lutein is the major carotenoid and is normally accompanied by about 3-6% zeaxanthin; in Lycium Chinese Mill (LCM) berries zeaxanthin is the major carotenoid and is completely free from lutein. Purification of lutein esters from marigold flowers was patented by Philip in 1977 (U.S. Pat. No. 4,048,203). The purified lutein esters by humans, upon ingestion, these compounds partially undergo hydrolysis in the presence of pancreatic secretions in the small intestine to regenerate free lutein which is then absorbed [Khachik et al. Pure & Appl. Chem., 63(1): 71-80, 1991].
A method for the purification of free lutein from extracts of marigold was first reported in 1991 [Tyzkowski and Hamilton, Poultry Sci., 70(3): 651-654, 1991]. However, this method was extremely time-consuming, uses harmful organic solvents, produced poor yield and it could not be a viable solution for commercial production.
In view of the important biological activity of lutein and zeaxanthin, one author developed a process for isolation, purification, and recrystallization of lutein from saponified marigold oleoresin which was patented in 1995 (Khachik, U.S. Pat. No. 5,382,714). The saponified marigold oleoresin was obtained from Kemin Industries (Des Moines, Iowa) and is normally prepared by extraction of dried Marigold petals with n-hexane, followed by saponification and solvent evaporation. To date, this process is the only available method for isolation and purification of lutein (containing 3-6% zeaxanthin) from marigold with purity greater than 97%. Later, another process for the isolation of lutein from a saponified marigold oleoresin has been reported wherein lutein can be obtained with 70-85% purity (U.S. Pat. No. 5,648,564, 1997). This process employs propylene glycol (40.9%, weight percent) and an aqueous alkali (18.2%, weight percent) to saponify hexane extract of dried marigold petals (marigold oleoresin, 40.9%, weight percent) containing lutein esters at 70° C. in 10 hours.
There are several major disadvantages with in listed processes; these are discussed as follows. The marigold oleoresin is prepared by extraction of dried marigold petals by boiling with n-hexane for extended time period. Since carotenoids in general, are sensitive to prolonged heat, this procedure can result in degradation or isomerization of these compounds.
The hydrolysis of lutein esters in the marigold oleoresin is generally conducted using aqueous solution along with alcohol and propylene glycol in which the fatty acid esters of lutein and zeaxanthin have very low solubility. As a result, this process requires high temperature up to 70° C. and 10 hours to complete the saponification. This can once again result in the degradation and isomerization of lutein and zeaxanthin.
Due to the high viscosity of propylene glycol, during handling and several purification steps, the saponified product is more subjected to high temperature ranging from 70 to 85° C. Exposure to heat in the presence of atmospheric air may result in oxidative degradation of carotenoids and formation of a number of the side products. In summary, the above patented process (U.S. Pat. No. 5,648,564) employs extraction and saponification of marigold flowers for lutein ester and lutein in two separate steps, followed by several purification steps. According to the authors, when the extraction and saponification steps were combined to simplify the procedure, the result was 64.7% reduction in the yield of lutein in comparison to the two-step extraction and saponification processes described by Khachik. Overall, these procedures are quite time-consuming and are carried out under harsh conditions and produces lutein with only 70-85% purity.
The earlier patent by the inventor (Khachik, U.S. Pat. No. 5,382,714) generally has limitations. This process also uses n-hexane as the extracting solvent and, at the last purification step, it employs dichloromethane and n-hexane as the recrystallization solvents to obtain lutein, containing 3-6% zeaxanthin, with purity of 97% or greater. Since according to the FDA, the use of dichloromethane and hexane in drug and food products should be limited and the lutein purified by these solvents should be thoroughly dried under high vacuum to remove residual solvents.
The patents and literature under the prior art have methods of search for developing purified free lutein or lutein esters and used principally several complex methods involving the use of hydrocarbon toxic solvents, chlorinated solvents and other hazardous chemical substance treatments so to make lutein either from marigold flower or green protein or juice concentrates. Also the methods of supercritical extractions earlier attempted in the arts either has first used the organic solvents followed by subsequent process of supercritical fluid extraction or two stage supercritical carbondioxide extraction process wherein the refined extracts have very low concentrations of lutein ester of limited use for making direct useful high percentage food, beverage and pharmaceutical variant forms like oil soluble dispersions, beadlets, granules or powders. Current investigation is taken as first ever art, superseding the drawbacks of previous investigations, in order to develop very high strength or purified lutein ester from marigold flower meal using a straight forward one stage very high pressure commercial supercritical extraction system which is facilitated with an advanced multiple-three product collection separator design. The three separator design facilitated SCF—CO2 system makes the extraction much simpler than the prior art methods to develop high strength and purity lutein ester which is used for making directly useful high percentage food, beverage and pharmaceutical variant forms like oil soluble dispersions, beadlets, granules or powders.